"He said to them, 'When you pray, say: Father...'" Luke 11. 2
And with that simple word "Father" Jesus launched a revolution. Because the word he used was the Aramaic equivalent of "Daddy". Jews of the time expected to address God formally in classical Hebrew, just as Muslims still chant the Quran in classical Arabic and Hindus read the Vedas in Sanskrit. But Jesus opened the door to communicating with God in one's own language.
Jokes abound as to what the language of heaven might be. The truth is that God is multi-lingual. And so the Christian Bible is composed of at least three languages (Hebrew, Aramaic and Greek) and wherever the Gospel is preached, fresh translations are made into local languages and even dialects.
Jesus went further and instructed his followers to avoid showy "religious" language and speak to our "heavenly father" from our hearts. And sometimes without words. Contemplatives reach for such close communion with God that words are no longer necessary, indeed they cease to be relevant, become distractions even. Yet here also we must be careful not to become exclusive or elitist in our attitude.
Prayer is a gift of God, in which we are invited by our Creator to draw close and enjoy his complete attention and intimacy. That is why Jesus advocates our approach being that of a child: simple, trusting, honest. "Ar n-Athair..., Our Father..."